Understanding the Geometry of Astrophysical Magnetic Fields (2009)
Broderick, Avery E., Blandford, Roger D.
Faraday rotation measurements have provided an invaluable technique with which to measure the properties of astrophysical magnetized plasmas. Unfortunately, typical observations provide information...
Detecting Changing Polarization Structures in Sagittarius A* with High Frequency VLBI (2009)
Fish, Vincent L., Doeleman, Sheperd S., Broderick, Avery E., Loeb, Abraham, Rogers, Alan E. E.
Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center. In the submillimeter regime, Sgr A*...
Signatures of Relativistic Helical Motion in the Rotation Measures of AGN Jets (2009)
Broderick, Avery E, Loeb, Abraham
Polarization has proved an invaluable tool for probing magnetic fields in relativistic jets. Maps of the intrinsic polarization vectors have provided the best evidence to date for uniform, toroidally...
The Event Horizon of Sagittarius A* (2009)
Broderick, Avery E., Loeb, Abraham, Narayan, Ramesh
Black hole event horizons, causally separating the external universe from compact regions of spacetime, are one of the most exotic predictions of General Relativity (GR). Until recently, their...
Imaging the Black Hole Silhouette of M87: Implications for Jet Formation and Black Hole Spin (2008)
Broderick, Avery E., Loeb, Abraham
The silhouette cast by the horizon of the supermassive black hole in M87 can now be resolved with the emerging millimeter very-long baseline interferometry (VLBI) capability. Despite being ~2000...
Using Millimeter VLBI to Constrain RIAF Models of Sagittarius A* (2008)
Fish, Vincent L., Broderick, Avery E., Doeleman, Sheperd S., Loeb, Abraham
The recent detection of Sagittarius A* at lambda = 1.3 mm on a baseline from Hawaii to Arizona demonstrates that millimeter wavelength very long baseline interferometry (VLBI) can now spatially...
Estimating the Parameters of Sgr A*'s Accretion Flow Via Millimeter VLBI (2008)
Broderick, Avery E., Fish, Vincent L., Doeleman, Sheperd S., Loeb, Abraham
Recent millimeter-VLBI observations of Sagittarius A* (Sgr A*) have, for the first time, directly probed distances comparable to the horizon scale of a black hole. This provides unprecedented access...
Methods for detecting flaring structures in Sagittarius A* with high frequency VLBI (2008)
Doeleman, Sheperd S., Fish, Vincent L., Broderick, Avery E., Loeb, Abraham, Rogers, Alan E. E.
The super massive black hole candidate, Sagittarius A*, exhibits variability from radio to X-ray wavelengths on time scales that correspond to < 10 Schwarzschild radii. We survey the potential of...
Detecting Flaring Structures in Sagittarius A* with (Sub)Millimeter VLBI (2008)
Fish, Vincent L., Doeleman, Sheperd S., Broderick, Avery E., Loeb, Abraham, Rogers, Alan E. E.
Multiwavelength monitoring observations of Sagittarius A* exhibit variability on timescales of minutes to hours, indicating emission regions localized near the event horizon....
Embedded Oscillating Starless Cores (2008)
Broderick, Avery E., Narayan, Ramesh, Keto, Eric, Lada, Charles J.
In a previous paper we demonstrated that non-radial hydrodynamic oscillations of a thermally-supported (Bonnor-Ebert) sphere embedded in a low-density, high-temperature medium persist for many...
Limits on the Position Wander of Sgr A* (2008)
Reid, Mark J., Broderick, Avery E., Loeb, Abraham, Honma, Mareki, Brunthaler, Andreas
We present measurements with the VLBA of the variability in the centroid position of Sgr A* relative to a background quasar at 7-mm wavelength. We find an average centroid wander of 71 +/- 45...
Oscillating Starless Cores: The Nonlinear Regime (2007)
Broderick, Avery E., Keto, Eric, Lada, Charles J., Narayan, Ramesh
In a previous paper, we modeled the oscillations of a thermally-supported (Bonnor-Ebert) sphere as non-radial, linear perturbations following a standard analysis developed for stellar pulsations. The...
Magnetic Helicity and the Relaxation of Fossil Fields (2007)
Broderick, Avery E., Narayan, Ramesh
In the absence of an active dynamo, purely poloidal magnetic field configurations are unstable to large-scale dynamical perturbations, and decay via reconnection on an Alfvenic timescale....
Where are all the gravastars? Limits upon the gravastar model from accreting black holes (2007)
Broderick, Avery E., Narayan, Ramesh
The gravastar model, which postulates a strongly correlated thin shell of anisotropic matter surrounding a region of anti-de Sitter space, has been proposed as an alternative to black holes. We...
On The Nature of the Compact Dark Mass at the Galactic Center (2005)
Broderick, Avery E., Narayan, Ramesh
We consider a model in which Sgr A*, the 3.5x10^6 M_sun supermassive black hole candidate at the Galactic Center, is a compact object with a surface. Given the very low quiescent luminosity of Sgr A*...
Radiative Transfer Along Rays in Curved Spacetimes (2005)
Radiative transfer in curved spacetimes has become increasingly important to understanding high-energy astrophysical phenomena and testing general relativity in the strong field limit. The equations...
Broderick, Avery E., Loeb, Abraham
Sub milli-arcsecond astrometry and imaging of the black hole Sgr A* at the Galactic centre may become possible in the near future at infrared and sub-millimetre wavelengths. Motivated by observations...
Broderick, Avery E., Loeb, Abraham
The inferred black hole in the Galactic center spans the largest angle on the sky among all known black holes. Forthcoming observational programs plan to localize or potentially resolve the image of...
Imaging Bright Spots in the Accretion Flow Near the Black Hole Horizon of Sgr A* (2005)
Broderick, Avery E., Loeb, Abraham
Images from the vicinity of the black hole horizon at the Galactic centre (Sgr A*) could be obtained in the near future with a Very Large Baseline Array of sub-millimetre telescopes. The recently...
Supernovae in Helium Star--Compact Object Binaries: A Possible Gamma-ray Burst Mechanism (2004)
Helium star--compact object binaries, and helium star--neutron star binaries in particular, are widely believed to be the progenitors of the observed double neutron star systems. In these, the second...
A multi-dimensional, adiabatic, hydrodynamics code for studying tidal excitation (2004)
Broderick, Avery E., Rathore, Yasser
We have developed a parallel, simple, and fast hydrodynamics code for multi-dimensional, self-gravitating, adiabatic flows. Our primary motivation is the study of the non-linear evolution of white...
Rathore, Yasser, Blandford, Roger D., Broderick, Avery E.
We consider the evolution of white dwarfs with compact object companions (specifically black holes with masses up to 10^6 solar masses, neutron stars, and other white dwarfs). We suppose that the...
A variational formalism for tidal excitation: non-rotating, homentropic stars (2002)
Rathore, Yasser, Broderick, Avery E., Blandford, Roger
We present a variational formalism for describing the dynamical evolution of an oscillating star with a point-mass companion in the linear, non-relativistic regime. This includes both the excitation...